The present invention relates to fiber reinforced resin structures and particularly to a method and apparatus for coating the fiber strands with resin. Fiber reinforced resin structures can utilize various fibers, for example, glass, carbon, boron, aramid, polyester or a combination of these fibers. Likewise, various resins may be used such as epoxies or polyesters. The invention is particularly adapted for use with resins having relatively short cure times or pot life. It is conventional in the molding of composite articles from fiber reinforced resin to coat the fibers with resin using an open bath or similar structure wherein the fibers are first passed through the bath and then a means for removing the excess resin. After coating, the fibers are used to form the composite article either by molding in a die, wrapping the coated fibers on a suited mandrel, or passing them through an extrusion die which will extrude the desired article.
Normally, the coating baths are open to the atmosphere and contain a relatively large quantity of resin which has previously been mixed with a suitable curing agent. Thus, it is necessary to use mixtures of resin and curing agent which have a relatively long cure time or pot life. This, in turn, necessitates some means for accelerating the cure time after the coated fiber has been formed in the desired shape. The most commonly used means is to apply heat to the composite to accelerate the cure time.
Another method that has been used in the past comprises placing the fiber reinforcement in the mold and then injecting the resin into the mold. This allows the use of mixtures of resin and curing agent having shorter cure times. While the shorter cure time resins can be used there is no assurance that all of the fiber reinforcing material will be equally coated by the resin curing agent mixture injected into the mold. Further, the fiber reinforcing material and resin may not be uniformly distributed throughout the article.